Endowment effect

The endowment effect is the tendency to place higher value on something you own or that's yours. For example, if someone shows you a new test tool, you might say, “Eh, it’s nice. I might use it.” But if you show off the same tool, you might say, “This tool is the best tool I’ve seen for this type of testing.” Once you own it, it’s value increases. The same is true for test data, processes you help develop, test ideas, etc...
BiasMichael Kelly